[ARM PATCH] 2232/2: S3C2410 - RTC driver

Patch from Ben Dooks

S3C2410/S3C2440 RTC driver using arch/arm/common/rtctime.c as
a base. Supports alarm, and periodic IRQ from 1 to 64Hz

Signed-off-by: Ben Dooks
Signed-off-by: Russell King

drivers/char/Kconfig

@@ -790,6 +790,14 @@ config DS1302
 	  will get access to the real time clock (or hardware clock) built
 	  into your computer.
 
+config S3C2410_RTC
+	bool "S3C2410 RTC Driver"
+	depends on ARCH_S3C2410
+	help
+	  RTC (Realtime Clock) driver for the clock inbuilt into the
+	  Samsung S3C2410. This can provide periodic interrupt rates
+	  from 1Hz to 64Hz for user programs, and wakeup from Alarm.
+
 config COBALT_LCD
 	bool "Support for Cobalt LCD"
 	depends on MIPS_COBALT

drivers/char/Makefile

@@ -64,6 +64,7 @@ obj-$(CONFIG_EFI_RTC) += efirtc.o
 obj-$(CONFIG_SGI_DS1286) += ds1286.o
 obj-$(CONFIG_SGI_IP27_RTC) += ip27-rtc.o
 obj-$(CONFIG_DS1302) += ds1302.o
+obj-$(CONFIG_S3C2410_RTC) += s3c2410-rtc.o
 ifeq ($(CONFIG_GENERIC_NVRAM),y)
   obj-$(CONFIG_NVRAM) += generic_nvram.o
 else

drivers/char/s3c2410-rtc.c

+/* drivers/char/s3c2410_rtc.c
+ *
+ * Copyright (c) 2004 Simtec Electronics <linux@simtec.co.uk>
+ *		      http://www.simtec.co.uk/products/SWLINUX/
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * S3C2410 Internal RTC Driver
+ *
+ *  Changelog:
+ *	08-Nov-2004	BJD	Initial creation
+ *	12-Nov-2004	BJD	Added periodic IRQ and PM code
+*/
+
+#include <linux/module.h>
+#include <linux/fs.h>
+#include <linux/string.h>
+#include <linux/init.h>
+#include <linux/device.h>
+#include <linux/interrupt.h>
+#include <linux/rtc.h>
+#include <linux/bcd.h>
+
+#include <asm/hardware.h>
+#include <asm/uaccess.h>
+#include <asm/io.h>
+#include <asm/irq.h>
+#include <asm/rtc.h>
+
+#include <asm/mach/time.h>
+
+#include <asm/hardware/clock.h>
+#include <asm/arch/regs-rtc.h>
+
+/* need this for the RTC_AF definitions */
+#include <linux/mc146818rtc.h>
+
+#undef S3C2410_VA_RTC
+#define S3C2410_VA_RTC s3c2410_rtc_base
+
+static struct resource *s3c2410_rtc_mem;
+
+static void __iomem *s3c2410_rtc_base;
+static int s3c2410_rtc_alarmno = NO_IRQ;
+static int s3c2410_rtc_tickno  = NO_IRQ;
+static int s3c2410_rtc_freq    = 1;
+
+static spinlock_t s3c2410_rtc_pie_lock = SPIN_LOCK_UNLOCKED;
+
+/* IRQ Handlers */
+
+static irqreturn_t s3c2410_rtc_alarmirq(int irq, void *id, struct pt_regs *r)
+{
+	rtc_update(1, RTC_AF | RTC_IRQF);
+	return IRQ_HANDLED;
+}
+
+static irqreturn_t s3c2410_rtc_tickirq(int irq, void *id, struct pt_regs *r)
+{
+	rtc_update(1, RTC_PF | RTC_IRQF);
+	return IRQ_HANDLED;
+}
+
+/* Update control registers */
+static void s3c2410_rtc_setaie(int to)
+{
+	unsigned int tmp;
+
+	pr_debug("%s: aie=%d\n", __FUNCTION__, to);
+
+	tmp = readb(S3C2410_RTCALM);
+
+	if (to)
+		tmp |= S3C2410_RTCALM_ALMEN;
+	else
+		tmp &= ~S3C2410_RTCALM_ALMEN;
+
+
+	writeb(tmp, S3C2410_RTCALM);
+}
+
+static void s3c2410_rtc_setpie(int to)
+{
+	unsigned int tmp;
+
+	pr_debug("%s: pie=%d\n", __FUNCTION__, to);
+
+	spin_lock_irq(&s3c2410_rtc_pie_lock);
+	tmp = readb(S3C2410_TICNT) & ~S3C2410_TICNT_ENABLE;
+
+	if (to)
+		tmp |= S3C2410_TICNT_ENABLE;
+
+	writeb(tmp, S3C2410_TICNT);
+	spin_unlock_irq(&s3c2410_rtc_pie_lock);
+}
+
+static void s3c2410_rtc_setfreq(int freq)
+{
+	unsigned int tmp;
+
+	spin_lock_irq(&s3c2410_rtc_pie_lock);
+	tmp = readb(S3C2410_TICNT) & S3C2410_TICNT_ENABLE;
+
+	s3c2410_rtc_freq = freq;
+
+	tmp |= (128 / freq)-1;
+
+	writeb(tmp, S3C2410_TICNT);
+	spin_unlock_irq(&s3c2410_rtc_pie_lock);
+}
+
+/* Time read/write */
+
+static void s3c2410_rtc_gettime(struct rtc_time *rtc_tm)
+{
+	unsigned int have_retried = 0;
+
+ retry_get_time:
+	rtc_tm->tm_min  = readb(S3C2410_RTCMIN);
+	rtc_tm->tm_hour = readb(S3C2410_RTCHOUR);
+	rtc_tm->tm_mday = readb(S3C2410_RTCDATE);
+	rtc_tm->tm_mon  = readb(S3C2410_RTCMON);
+	rtc_tm->tm_year = readb(S3C2410_RTCYEAR);
+	rtc_tm->tm_sec  = readb(S3C2410_RTCSEC);
+
+	/* the only way to work out wether the system was mid-update
+	 * when we read it is to check the second counter, and if it
+	 * is zero, then we re-try the entire read
+	 */
+
+	if (rtc_tm->tm_sec == 0 && !have_retried) {
+		have_retried = 1;
+		goto retry_get_time;
+	}
+
+	pr_debug("read time %02x.%02x.%02x %02x/%02x/%02x\n",
+		 rtc_tm->tm_year, rtc_tm->tm_mon, rtc_tm->tm_mday,
+		 rtc_tm->tm_hour, rtc_tm->tm_min, rtc_tm->tm_sec);
+
+	BCD_TO_BIN(rtc_tm->tm_sec);
+	BCD_TO_BIN(rtc_tm->tm_min);
+	BCD_TO_BIN(rtc_tm->tm_hour);
+	BCD_TO_BIN(rtc_tm->tm_mday);
+	BCD_TO_BIN(rtc_tm->tm_mon);
+	BCD_TO_BIN(rtc_tm->tm_year);
+
+	rtc_tm->tm_year += 100;
+	rtc_tm->tm_mon -= 1;
+}
+
+
+static int s3c2410_rtc_settime(struct rtc_time *tm)
+{
+	/* the rtc gets round the y2k problem by just not supporting it */
+
+	if (tm->tm_year < 100)
+		return -EINVAL;
+
+	writeb(BIN2BCD(tm->tm_sec),  S3C2410_RTCSEC);
+	writeb(BIN2BCD(tm->tm_min),  S3C2410_RTCMIN);
+	writeb(BIN2BCD(tm->tm_hour), S3C2410_RTCHOUR);
+	writeb(BIN2BCD(tm->tm_mday), S3C2410_RTCDATE);
+	writeb(BIN2BCD(tm->tm_mon + 1), S3C2410_RTCMON);
+	writeb(BIN2BCD(tm->tm_year - 100), S3C2410_RTCYEAR);
+
+	return 0;
+}
+
+static void s3c2410_rtc_getalarm(struct rtc_wkalrm *alrm)
+{
+	struct rtc_time *alm_tm = &alrm->time;
+	unsigned int alm_en;
+
+	alm_tm->tm_sec  = readb(S3C2410_ALMSEC);
+	alm_tm->tm_min  = readb(S3C2410_ALMMIN);
+	alm_tm->tm_hour = readb(S3C2410_ALMHOUR);
+	alm_tm->tm_mon  = readb(S3C2410_ALMMON);
+	alm_tm->tm_mday = readb(S3C2410_ALMDATE);
+	alm_tm->tm_year = readb(S3C2410_ALMYEAR);
+
+	alm_en = readb(S3C2410_RTCALM);
+
+	pr_debug("read alarm %02x %02x.%02x.%02x %02x/%02x/%02x\n",
+		 alm_en,
+		 alm_tm->tm_year, alm_tm->tm_mon, alm_tm->tm_mday,
+		 alm_tm->tm_hour, alm_tm->tm_min, alm_tm->tm_sec);
+
+
+	/* decode the alarm enable field */
+
+	if (alm_en & S3C2410_RTCALM_SECEN) {
+		BCD_TO_BIN(alm_tm->tm_sec);
+	} else {
+		alm_tm->tm_sec = 0xff;
+	}
+
+	if (alm_en & S3C2410_RTCALM_MINEN) {
+		BCD_TO_BIN(alm_tm->tm_min);
+	} else {
+		alm_tm->tm_min = 0xff;
+	}
+
+	if (alm_en & S3C2410_RTCALM_HOUREN) {
+		BCD_TO_BIN(alm_tm->tm_hour);
+	} else {
+		alm_tm->tm_hour = 0xff;
+	}
+
+	if (alm_en & S3C2410_RTCALM_DAYEN) {
+		BCD_TO_BIN(alm_tm->tm_mday);
+	} else {
+		alm_tm->tm_mday = 0xff;
+	}
+
+	if (alm_en & S3C2410_RTCALM_MONEN) {
+		BCD_TO_BIN(alm_tm->tm_mon);
+		alm_tm->tm_mon -= 1;
+	} else {
+		alm_tm->tm_mon = 0xff;
+	}
+
+	if (alm_en & S3C2410_RTCALM_YEAREN) {
+		BCD_TO_BIN(alm_tm->tm_year);
+	} else {
+		alm_tm->tm_year = 0xffff;
+	}
+
+	/* todo - set alrm->enabled ? */
+}
+
+static int s3c2410_rtc_setalarm(struct rtc_wkalrm *alrm)
+{
+	struct rtc_time *tm = &alrm->time;
+	unsigned int alrm_en;
+
+	pr_debug("s3c2410_rtc_setalarm: %d, %02x.%02x.%02x %02x/%02x/%02x\n",
+		 alrm->enabled,
+		 tm->tm_year & 0xff, tm->tm_mon & 0xff, tm->tm_mday & 0xff,
+		 tm->tm_hour, tm->tm_min, tm->tm_sec);
+
+	if (alrm->enabled || 1) {
+		alrm_en = readb(S3C2410_RTCALM) & S3C2410_RTCALM_ALMEN;
+		writeb(0x00, S3C2410_RTCALM);
+
+		if (tm->tm_sec < 60) {
+			alrm_en |= S3C2410_RTCALM_SECEN;
+			writeb(BIN2BCD(tm->tm_sec), S3C2410_ALMSEC);
+		}
+
+		if (tm->tm_min < 60) {
+			alrm_en |= S3C2410_RTCALM_MINEN;
+			writeb(BIN2BCD(tm->tm_min), S3C2410_ALMMIN);
+		}
+
+		if (tm->tm_hour < 24) {
+			alrm_en |= S3C2410_RTCALM_HOUREN;
+			writeb(BIN2BCD(tm->tm_hour), S3C2410_ALMHOUR);
+		}
+
+		pr_debug("setting S3C2410_RTCALM to %08x\n", alrm_en);
+
+		writeb(alrm_en, S3C2410_RTCALM);
+		enable_irq_wake(s3c2410_rtc_alarmno);
+	} else {
+		alrm_en = readb(S3C2410_RTCALM);
+		alrm_en &= ~S3C2410_RTCALM_ALMEN;
+		writeb(alrm_en, S3C2410_RTCALM);
+		disable_irq_wake(s3c2410_rtc_alarmno);
+	}
+
+	return 0;
+}
+
+static int s3c2410_rtc_ioctl(unsigned int cmd, unsigned long arg)
+{
+	switch (cmd) {
+	case RTC_AIE_OFF:
+	case RTC_AIE_ON:
+		s3c2410_rtc_setaie((cmd == RTC_AIE_ON) ? 1 : 0);
+		return 0;
+
+	case RTC_PIE_OFF:
+	case RTC_PIE_ON:
+		s3c2410_rtc_setpie((cmd == RTC_PIE_ON) ? 1 : 0);
+		return 0;
+
+	case RTC_IRQP_READ:
+		return put_user(s3c2410_rtc_freq, (unsigned long __user *)arg);
+
+	case RTC_IRQP_SET:
+		if (arg < 1 || arg > 64)
+			return -EINVAL;
+
+		if (!capable(CAP_SYS_RESOURCE))
+			return -EACCES;
+
+		/* check for power of 2 */
+
+		if ((arg & (arg-1)) != 0)
+			return -EINVAL;
+
+		pr_debug("s3c2410_rtc: setting frequency %ld\n", arg);
+
+		s3c2410_rtc_setfreq(arg);
+		return 0;
+
+	case RTC_UIE_ON:
+	case RTC_UIE_OFF:
+		return -EINVAL;
+	}
+
+	return -EINVAL;
+}
+
+static int s3c2410_rtc_proc(char *buf)
+{
+	unsigned int rtcalm = readb(S3C2410_RTCALM);
+	unsigned int ticnt = readb (S3C2410_TICNT);
+	char *p = buf;
+
+	p += sprintf(p, "alarm_IRQ\t: %s\n",
+		     (rtcalm & S3C2410_RTCALM_ALMEN) ? "yes" : "no" );
+	p += sprintf(p, "periodic_IRQ\t: %s\n",
+		     (ticnt & S3C2410_TICNT_ENABLE) ? "yes" : "no" );
+	p += sprintf(p, "periodic_freq\t: %d\n", s3c2410_rtc_freq);
+
+	return p - buf;
+}
+
+static int s3c2410_rtc_open(void)
+{
+	int ret;
+
+	ret = request_irq(s3c2410_rtc_alarmno, s3c2410_rtc_alarmirq,
+			  SA_INTERRUPT,  "s3c2410-rtc alarm", NULL);
+
+	if (ret)
+		printk(KERN_ERR "IRQ%d already in use\n", s3c2410_rtc_alarmno);
+
+	ret = request_irq(s3c2410_rtc_tickno, s3c2410_rtc_tickirq,
+			  SA_INTERRUPT,  "s3c2410-rtc tick", NULL);
+
+	if (ret) {
+		printk(KERN_ERR "IRQ%d already in use\n", s3c2410_rtc_tickno);
+		goto tick_err;
+	}
+
+	return ret;
+
+ tick_err:
+	free_irq(s3c2410_rtc_alarmno, NULL);
+	return ret;
+}
+
+static void s3c2410_rtc_release(void)
+{
+	/* do not clear AIE here, it may be needed for wake */
+
+	s3c2410_rtc_setpie(0);
+	free_irq(s3c2410_rtc_alarmno, NULL);
+	free_irq(s3c2410_rtc_tickno, NULL);
+}
+
+static struct rtc_ops s3c2410_rtcops = {
+	.owner		= THIS_MODULE,
+	.open		= s3c2410_rtc_open,
+	.release	= s3c2410_rtc_release,
+	.ioctl		= s3c2410_rtc_ioctl,
+	.read_time	= s3c2410_rtc_gettime,
+	.set_time	= s3c2410_rtc_settime,
+	.read_alarm	= s3c2410_rtc_getalarm,
+	.set_alarm	= s3c2410_rtc_setalarm,
+	.proc	        = s3c2410_rtc_proc,
+};
+
+static void s3c2410_rtc_enable(struct device *dev, int en)
+{
+	unsigned int tmp;
+
+	if (s3c2410_rtc_base == NULL)
+		return;
+
+	if (!en) {
+		tmp = readb(S3C2410_RTCCON);
+		writeb(tmp & ~S3C2410_RTCCON_RTCEN, S3C2410_RTCCON);
+
+		tmp = readb(S3C2410_TICNT);
+		writeb(tmp & ~S3C2410_TICNT_ENABLE, S3C2410_TICNT);
+	} else {
+		/* re-enable the device, and check it is ok */
+
+		if ((readb(S3C2410_RTCCON) & S3C2410_RTCCON_RTCEN) == 0){
+			dev_info(dev, "rtc disabled, re-enabling\n");
+
+			tmp = readb(S3C2410_RTCCON);
+			writeb(tmp | S3C2410_RTCCON_RTCEN , S3C2410_RTCCON);
+		}
+
+		if ((readb(S3C2410_RTCCON) & S3C2410_RTCCON_CNTSEL)){
+			dev_info(dev, "removing S3C2410_RTCCON_CNTSEL\n");
+
+			tmp = readb(S3C2410_RTCCON);
+			writeb(tmp& ~S3C2410_RTCCON_CNTSEL , S3C2410_RTCCON);
+		}
+
+		if ((readb(S3C2410_RTCCON) & S3C2410_RTCCON_CLKRST)){
+			dev_info(dev, "removing S3C2410_RTCCON_CLKRST\n");
+
+			tmp = readb(S3C2410_RTCCON);
+			writeb(tmp & ~S3C2410_RTCCON_CLKRST, S3C2410_RTCCON);
+		}
+	}
+}
+
+static int s3c2410_rtc_remove(struct device *dev)
+{
+	unregister_rtc(&s3c2410_rtcops);
+
+	s3c2410_rtc_setpie(0);
+	s3c2410_rtc_setaie(0);
+
+	if (s3c2410_rtc_mem != NULL) {
+		pr_debug("s3c2410_rtc: releasing s3c2410_rtc_mem\n");
+		iounmap(s3c2410_rtc_base);
+		release_resource(s3c2410_rtc_mem);
+		kfree(s3c2410_rtc_mem);
+	}
+
+	return 0;
+}
+
+static int s3c2410_rtc_probe(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct resource *res;
+	int ret;
+
+	pr_debug("%s: probe=%p, device=%p\n", __FUNCTION__, pdev, dev);
+
+	/* find the IRQs */
+
+	s3c2410_rtc_tickno = platform_get_irq(pdev, 1);
+	if (s3c2410_rtc_tickno <= 0) {
+		dev_err(dev, "no irq for rtc tick\n");
+		return -ENOENT;
+	}
+
+	s3c2410_rtc_alarmno = platform_get_irq(pdev, 0);
+	if (s3c2410_rtc_alarmno <= 0) {
+		dev_err(dev, "no irq for alarm\n");
+		return -ENOENT;
+	}
+
+	pr_debug("s3c2410_rtc: tick irq %d, alarm irq %d\n",
+		 s3c2410_rtc_tickno, s3c2410_rtc_alarmno);
+
+	/* get the memory region */
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (res == NULL) {
+		dev_err(dev, "failed to get memory region resource\n");
+		return -ENOENT;
+	}
+
+	s3c2410_rtc_mem = request_mem_region(res->start, res->end-res->start+1,
+				     pdev->name);
+
+	if (s3c2410_rtc_mem == NULL) {
+		dev_err(dev, "failed to reserve memory region\n");
+		ret = -ENOENT;
+		goto exit_err;
+	}
+
+	s3c2410_rtc_base = ioremap(res->start, res->end - res->start + 1);
+	if (s3c2410_rtc_base == NULL) {
+		dev_err(dev, "failed ioremap()\n");
+		ret = -EINVAL;
+		goto exit_err;
+	}
+
+	s3c2410_rtc_mem = res;
+	pr_debug("s3c2410_rtc_base=%p\n", s3c2410_rtc_base);
+
+ 	pr_debug("s3c2410_rtc: RTCCON=%02x\n", readb(S3C2410_RTCCON));
+
+	/* check to see if everything is setup correctly */
+
+	s3c2410_rtc_enable(dev, 1);
+
+ 	pr_debug("s3c2410_rtc: RTCCON=%02x\n", readb(S3C2410_RTCCON));
+
+	s3c2410_rtc_setfreq(s3c2410_rtc_freq);
+
+	/* register RTC and exit */
+
+	register_rtc(&s3c2410_rtcops);
+	return 0;
+
+ exit_err:
+	dev_err(dev, "error %d during initialisation\n", ret);
+
+	return ret;
+}
+
+#ifdef CONFIG_PM
+
+/* S3C2410 RTC Power management control */
+
+static struct timespec s3c2410_rtc_delta;
+
+static int ticnt_save;
+
+static int s3c2410_rtc_suspend(struct device *dev, u32 state, u32 level)
+{
+	struct rtc_time tm;
+	struct timespec time;
+
+	time.tv_nsec = 0;
+
+	if (level == SUSPEND_POWER_DOWN) {
+		/* save TICNT for anyone using periodic interrupts */
+
+		ticnt_save = readb(S3C2410_TICNT);
+
+		/* calculate time delta for suspend */
+
+		s3c2410_rtc_gettime(&tm);
+		rtc_tm_to_time(&tm, &time.tv_sec);
+		save_time_delta(&s3c2410_rtc_delta, &time);
+		s3c2410_rtc_enable(dev, 0);
+	}
+
+	return 0;
+}
+
+static int s3c2410_rtc_resume(struct device *dev, u32 level)
+{
+	struct rtc_time tm;
+	struct timespec time;
+
+	time.tv_nsec = 0;
+
+	s3c2410_rtc_enable(dev, 1);
+	s3c2410_rtc_gettime(&tm);
+	rtc_tm_to_time(&tm, &time.tv_sec);
+	restore_time_delta(&s3c2410_rtc_delta, &time);
+
+	writeb(ticnt_save, S3C2410_TICNT);
+	return 0;
+}
+#else
+#define s3c2410_rtc_suspend NULL
+#define s3c2410_rtc_resume  NULL
+#endif
+
+static struct device_driver s3c2410_rtcdrv = {
+	.name		= "s3c2410-rtc",
+	.bus		= &platform_bus_type,
+	.probe		= s3c2410_rtc_probe,
+	.remove		= s3c2410_rtc_remove,
+	.suspend	= s3c2410_rtc_suspend,
+	.resume		= s3c2410_rtc_resume,
+};
+
+static char __initdata banner[] = "S3C2410 RTC, (c) 2004 Simtec Electronics\n";
+
+static int __init s3c2410_rtc_init(void)
+{
+	printk(banner);
+	return driver_register(&s3c2410_rtcdrv);
+}
+
+static void __exit s3c2410_rtc_exit(void)
+{
+	driver_unregister(&s3c2410_rtcdrv);
+}
+
+module_init(s3c2410_rtc_init);
+module_exit(s3c2410_rtc_exit);
+
+MODULE_DESCRIPTION("S3C24XX RTC Driver");
+MODULE_AUTHOR("Ben Dooks, <ben@simtec.co.uk>");
+MODULE_LICENSE("GPL");